The present invention relates to a terminal structure to which an electronic component such as a semiconductor chip is to be bonded.
Some types of liquid crystal displays, for example, comprise a liquid display panel, a circuit board for supplying data and control signals to the liquid crystal panel, and a flexible wiring board connecting the liquid crystal panel and the circuit board. The flexible wiring board may be one called COF (Chip On Film) that comprises a film substrate and a semiconductor chip mounted on the film substrate. The semiconductor chip is, for example, an LSI for driving the liquid crystal panel.
Such a conventional flexible wiring board has connection terminals provided on the upper surface of the film substrate and connection electrodes provided on the lower surface of the semiconductor chip. FIG. 8 shows the positional relation between the connection terminals and the connection electrodes. The connection terminals 1 have been formed by etching a copper foil or the like laminated with the film substrate (not shown) by direct deposition or using adhesive. They are straight, arranged parallel to one another and spaced at a predetermined pitch. The connection electrodes 2 (bump electrodes), which are provided on the lower surface of the semiconductor chip, are square in cross-section, arranged side by side and spaced at the same pitch as the connection terminals 1. The electrodes 2 are connected to the connection terminals 1 by an anisotropic, electrically conductive adhesive (not shown). The semiconductor chip is thereby mounted on the film substrate.
Each side of the square connection electrodes 2 has a length L, and the connection electrodes 2 are arranged at pitch P. The gap D between any two adjacent connection electrodes 2 is therefore (Pxe2x88x92L). Assume that the precision of bonding the semiconductor chip to the film substrate is xc2x1A. Then, it is necessary to prevent each connection terminal 1 from being displaced to have its one edge coming out of the left or right side of one connection electrode 2. To this end, the width T of the connection terminals 1 must be (Lxe2x88x922A) at maximum. That is, in view of the bonding precision of xc2x1A, the width T must be (Lxe2x88x922A) at maximum in order to reduce the side length L of the connection electrodes 1 and the pitch P thereby to achieve fine pitching. Consequently, the width T of the connection terminals 1 is far less than the side length L of the connection electrodes 2. The peeling strength that the terminals 1 have with respect to the film substrate is inevitably small. Particularly, the end portions of each connection terminal 1 are likely to peel from the film substrate. There are inevitably limitations to the fine pitching.
The object of the present invention is to provide a terminal structure to which an electronic component can be bonded with high adhesion strength even if the terminals are arranged at a short pitch.
The terminal structure according to this invention comprises a substrate and a plurality of connection terminals. The connection terminals are arranged on the substrate at a predetermined pitch. Each connection terminal has an electrode-connecting part and a reinforcing part. The electrode-connecting part has a predetermined width. The reinforcing part is provided near the electrode-connecting part and has a maximum width greater than the width of the electrode-connecting part.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.